Elastic brake body

ABSTRACT

A brake body, for a brake pad or a disk brake lining, comprising: a support body having at least one recess; at least one friction material element arranged in the at least one recess with the at least one friction material element being movably inserted in a longitudinal direction in the at least one recess and, together with the support body, forming a friction surface; and a shear-elastic intermediate layer inserted in a space along the at least one recess between the at least one friction material element and the support body.

[0001] The invention relates to a brake body, particularly a brake pador a disk brake lining, comprising a support body with at least onerecess as well as at least one friction material element arranged in therecess and movably disposed along the recess, the support body and thefriction material element together forming a friction surface, accordingto the preamble of claim 1.

[0002] Two large categories of friction brakes exist particularly in thecase of rail vehicles. On the one hand, these are the so-called shoebrakes and, on the other hand, the disk brakes.

[0003] The shoe brake is a friction brake for rail vehicles which has acost-effective construction because, in the case of such a brakingdevice, only one application device is required by means of which abrake pad is pressed onto the running surface of the rail wheel. Withrespect to the construction of pad brakes, reference is made to “Brakesfor Rail Vehicles”, Manual—Brake-Related Terms and Values, Knorr-BremseAG München, 1990, Pages 22-23, and Page 41.

[0004] Disadvantages of the pad brake according to the prior art areparticularly the high stressing of the wheel running surface, whichshortens the service life of the wheel, as well as a roughening of thewheel running surface and rail corrugation. Particularly the lattereffects result in a loud running noise during the rolling of the wheel.These disadvantages of the pad brake have favored the development andthe use of the disk brakes in modern railroad cars.

[0005] In the case of a disk brake, the brake disks are mounted on bothsides of the wheel body. The brake linings act upon the brake disk. Thepertaining wheel is braked as a result of the friction force.

[0006] Concerning the construction of disk brakes according to the priorart, reference is made to “Brakes for Rail Vehicles”,Manual—Brake-Related Terms and Values, Knorr-Bremse AG Müinchen, Page50.

[0007] Brake pads with recesses are known from a plurality ofpublications. Thus German Patent Document DE-C-277902 shows a brake padwith recesses into which a felt material is inserted. The felt materialprotrudes beyond the support body, so that no joint friction surface isformed with the support body.

[0008] The brake pad known from German Patent Document DE-U-29500977comprises bores which receive stoppers made of a friction material. Thestoppers are fastened by means of a screw on the support body; that is,they are disposed in a rigid manner. An elastic or rocking bearing ofthe individual friction material blocks has not become known from GermanPatent Document DE-U-29500977.

[0009] The brake linings known from German Patent DocumentsDE-A-4301006, DE-A-4436457 and DE-U-9307017 comprise elastically orrockingly disposed friction material blocks. These are arranged directlyon the support body and particularly form no cohesive friction materialsurface with the support body.

[0010] In the case of the pad brakes as well as in the case of the disksbrakes, a general problem exists with respect to the contact pressingbetween brake bodies, that is, the brake pad and the wheel as well asthe brake lining and the bake disk respectively.

[0011] As a result of thermal expansions of the brake body or of thewheel or the disk as well as their wear, the actual braking value of theabove-mentioned friction brakes is always significantly lower than thevalue which is theoretically possible according to the matter constants.

[0012] In the case of pad brakes, there is also the factor that, forrunning-related reasons, the wheel running surface forms anon-developable surface. Therefore the brake pad often rests on thewheel running surface only in a spot-type manner or forms an extendedcontact. Because of this contact, the pad brake is extremelyoverstressed.

[0013] Another problem of the above-described braking systems is thecontact pattern which is insufficient, for example, because of thermalexpansions and axle shifting. Generally, the contact pattern is thepoorer, the harder the material. The poor contact pattern results inrail corrugation or in cracking in the wheel running surfaces andtherefore in a high development of noise during braking.

[0014] A brake body with friction material elements is known from GermanPatent Document DE 198 40 065. The friction material elements areinserted in recesses in a support body and are disposed to be movablelongitudinally of the recesses. By means of this construction, it ispossible for the support body and the friction material elements to forma joint friction surface. The described friction material elements havea cylindrical construction, and devices for reducing the friction areconnected between the receiving wall of the support body and thefriction material elements. These devices for reducing the friction maypreferably be sleeves made of sheet metal.

[0015] However, the illustrated construction has several disadvantages.Despite the preferably inserted devices for reducing friction, these aresubjected to wear because, during each movement of the friction materialelement relative to the support body, the frictional material element orthe surrounding sleeve slides along the wall of the recess in thesupport body. Since considerable forces transversely to the slidingdirection of the friction material elements occur during the brakingoperation, the friction material elements are tilted or pressed againstthe interior wall of the recess in the support body, so that, during arelative movement of the friction material element with respect to thesupport body, a considerable friction force occurs which results inrapid wear. This may lead particularly to a widening of the recess inthe support body, which creates the risk that the friction materialelement will become detached or fall out of the recess. Brief inspectionperiods and a frequent exchange of the friction material elements aretherefore required, and the widened recesses have to be reworked on aregular basis.

[0016] It is therefore an object of the invention to provide a brakebody, particularly for pad brakes and disk brakes, by means of which theabove-mentioned disadvantages are overcome. In particular, the frictionbetween the friction material element and the support body is to beavoided and the falling-out of the friction material element is to beeffectively prevented. The construction should permit a cost-effectiveproduction, assembly and maintenance.

[0017] According to the invention, this is achieved in that thedisplacement of the friction material elements in the longitudinaldirection of the recesses in the support body no longer takes place bysliding but by compression. According to the invention, a shear-elasticintermediate layer is inserted in the space along the recess between thefriction material element and the support body. During the braking, thislayer allows a compression of the friction material element into therecess in the support body into which it is inserted so that the supportbody and the friction material element together form a friction surface.

[0018] The spring force, which counteracts the pressing of the frictionmaterial element into the recess, in this case, can be applied by theshear elastic layer alone or by a conventional elastic or resilientbearing between the end of the friction material element opposed to thebraking area and the base of the recess. When the friction materialelement in its longitudinal direction is disposed on an elastic element,the shear-elastic intermediate layer and the elastic element mayadvantageously comprise the same material. It is a prerequisite herethat the material have pressure-elastic as well as shear-elasticcharacteristics. As a result, the manufacturing costs can be reduced andthe number of the used materials can be limited. In a particularlycost-effective manner, the pressure-elastic element and theshear-elastic intermediate layer can be constructed as one component.

[0019] The shear-elastic layer according to the invention comprisesdifferent embodiments. For example, a filling should be mentionedbetween the friction material element and the support body. Furthermore,a shear-elastic intermediate layer is conceivable which is applied as ahose onto the friction material element. Advantageously, the frictionmaterial element can also be coated with a shear-elastic material. Thelatter constructions permit, in addition to the simple production, alsoan easy mounting or a simple exchange. Naturally, the shear-elasticlayer can also be applied to the support body; that is, it can be placedin its recess.

[0020] In order to prevent a falling-out of the friction materialelement, the friction material element, the shear-elastic layer and thesupport body can be fixedly connected and particularly glued to oneanother. However, constructions are also conceivable in which theshear-elastic layer is applied only to the friction material element oronly to the support body and only adheres to the respective otherelement. Naturally, the shear-elastic layer may also be placed as anindependent component between the friction material element and thesupport body.

[0021] An additional effective securing with respect to a falling-outcan be achieved in that the frictional material element has a conicalconstruction. In this case, the cone converges (tapers? translator) inthe direction of the braking area, so that a falling-out becomesimpossible.

[0022] In contrast, if the cone spreads in the direction of the brakingarea, particularly if the shear-elastic layer also has pressure elasticcharacteristics, the surface pressure between the friction materialelement and the support body will be reduced because the pressure in thelongitudinal direction of the recess is distributed to a larger area.The two conical courses may be combined with one another in order to beable to simultaneously utilize the above-mentioned positive effects.

[0023] The friction material element may be enclosed at least indirectlyby the support body from all sides with the exception of the side of thebraking area. However, a particularly advantageous construction providesthe bearing of the friction material element by means of its sideopposed to the braking area indirectly on a carrier plate. This isparticularly advantageous when the friction material element has aconically converging construction in the direction of its braking areabecause it can then be inserted from the side of the carrier plate intothe also conical recess of the support body. In the case of aconstruction with a carrier plate, two possibilities of the bearing areconceivable. On the one hand, a pressure-elastic element may be placedbetween the friction material element and the carrier plate. On theother hand, at least in the area of the bearing of the friction materialelement, the carrier plate itself may have an elastic construction andthus exercise the required force onto the friction material element.

[0024] The essential elements of the invention will be described in thefollowing by means of the embodiments illustrated in the figures.

[0025]FIG. 1 is a sectional view of a brake body according to theinvention having a cylindrical friction material element;

[0026]FIG. 2a is a sectional view of a brake body according to theinvention having friction material element which conically spreads inthe direction of the braking area;

[0027]FIG. 2b is a sectional view of a brake body according to theinvention having a friction material element which conically convergesin the direction of the braking area;

[0028]FIG. 3a is a view of a brake body according to the invention whichrests against an even wheel running surface and is disposed by means ofspring elements;

[0029]FIG. 3b is a view of the brake body according to the inventionwhich rests against an uneven wheel running surface and is disposed bymeans of spring elements.

[0030]FIG. 1 is a sectional view of an elastic brake body according tothe invention. The brake body comprises a carrier plate 1, a supportbody 2 and a friction material element 3. The support body 2 has arecess 6. The friction material element 3 is movably in the longitudinaldirection of the recess inserted into the recess 6. The frictionmaterial element 3 is disposed on a spring element 4. The spring element4 is supported on the carrier plate 1. A shear-elastic intermediatelayer 5 is inserted into the space along the recess 6 between thefriction material element 3 and the support body 2. In the inoperativeposition, the friction material element 3 protrudes beyond the frictionsurface 9 of the support body 2. During the braking, the frictionmaterial element 3 is pressed onto the spring element 4, in which casethe shear-elastic filling 5 ensures a compression without any wear byfriction between the friction material element 3 and the support body 2.As a result of the compression, the support body 2 and the frictionmaterial element 3 form a joint friction surface during the braking,which is composed of the friction surface 9 of the support body 2 and ofthe friction surface 10 of the friction material element 3.

[0031]FIG. 2a shows an elastic brake body according to the inventionwhich has a conical friction material element 3. The constructionillustrated in FIG. 2a shows a conical friction material element 3 whichhas a diverging cross-section in the direction of the braking area. As aresult of the construction according to the invention having ashear-elastic intermediate layer 5 which here advantageously also haspressure-elastic characteristics, the surface pressure between thefrictional material element 3 and the support body 2 during the brakingoperation is reduced by a larger effective contact surface. According tothe invention, a falling-out of the friction material element can beprevented in that the friction material element 3, the shear-elasticintermediate layer 5 and the support body 2 are fixedly connected withone another, particularly glued to one another.

[0032]FIG. 2b shows a brake body according to the invention which has aconically constructed friction material element 3 which converges in itscross-section in the direction of the braking area. As in FIG. 2a, it isdisposed on a carrier plate 1 by means of a spring element 4. Accordingto the invention, a shear-elastic intermediate layer 5 is inserted inthe space between the friction material element 3 and the support body 2in the longitudinal direction of the recess. As a result of the conicalconstruction illustrated here, a falling-out of the friction materialelement 3 is impossible. The construction with the carrier plate 1permits a simple mounting of the friction material element 3 in thesupport body 2 while the carrier plate 1 is dismounted.

[0033] Naturally, a combination of the characteristics illustrated inFIGS. 2a and 2 b is possible. For the mounting of such a doublyconically constructed friction material element, the carrier plate mustbe provided with a conical recess corresponding to the course of thecontour of the end of the friction material element which is opposed tothe braking area.

[0034]FIG. 3a shows a brake body according to the invention which restsagainst an even wheel running surface 8. In the illustrated embodiment,the friction material elements 3 are disposed by means of a springelement 4 on the base 7 of the recesses 6 in the support body 2. Theshear-elastic intermediate layer 5 prevents the friction between thefriction material elements 3 and the support body 2.

[0035]FIG. 3b shows a brake body according to the invention which restsagainst an uneven wheel running surface 8. Corresponding to the contourof the wheel running surface 8, the friction material elements 3 arecompressed or rebounded. The shear-elastic intermediate layer 5 preventsthe occurrence of friction between the friction material elements 3 andthe support body 2. The spring force is composed of the shear-elasticspring force of the shear-elastic intermediate layer 5 and of thepressure spring force of the spring elements 4.

[0036] Thus, by means of the brake body according to the invention, abrake pad or a disk brake lining is indicated for the first time whichis distinguished by a cost-effective construction and in the case ofwhich it is possible for the first time to completely avoid theoccurrence of a wearing-away friction between the friction materialelement and the support body. The mounting is cost-effective and thefriction material element is optimally secured against a falling-out.Thus, a durable and secure operation is ensured.

List of Reference Numbers

[0037] Carrier plate

[0038] support body

[0039] friction material element

[0040] spring element

[0041] shear-elastic filling

[0042] recess

[0043] base of recess

[0044] wheel running surface

[0045] friction surface of the support body

[0046] friction surface of the friction material element

1. Brake body, particularly a brake pad or a disk brake lining,comprising 1.1 a support body (2) having at least one recess (6), 1.2 atleast one friction material element (3) arranged in the recess, 1.3 thefriction material element (3) being movably disposed in the directionalong the recess (6) and, together with the support body (2), forming afriction surface (9, 10), characterized in that 1.4 a shear-elasticintermediate layer (5) is inserted in the space along the recess (6)between the friction material element (3) and the support body (2). 2.Brake body according to claim 1, characterized in that the frictionmaterial element (3) is disposed in its longitudinal direction on anelastic element.
 3. Brake body according to claim 2, characterized inthat the elastic element comprises a spring element (4).
 4. Brake bodyaccording to claim 2, characterized in that the shear-elastic layerintermediate layer (5) and the elastic element comprise the samematerial.
 5. Brake body according to claim 4, characterized in that theshear-elastic intermediate layer (5) and the elastic element areconstructed as one component.
 6. Brake body according to one of claims 1to 5, characterized in that the shear-elastic intermediate layer (5) isinserted as a filling between the friction material element (3) and thesupport body (2).
 7. Brake body according to one of claims 1 to 5,characterized in that the shear-elastic intermediate layer (5) isapplied as a hose to the friction material element (3).
 8. Brake bodyaccording to one of claims 1 to 5 characterized in that theshear-elastic intermediate layer (5) is applied as a coating to thefriction material element (3).
 9. Brake body according to one of claims1 to 8, characterized in that the friction material element (3) and theshear-elastic intermediate layer (5) and the support body (2) are firmlyconnected with one another, particularly glued to one another.
 10. Brakebody according to one of claims 1 to 9, characterized in that thefriction material element (3) has a conical construction in thelongitudinal direction.
 11. Brake body according to one of claims 1 to10, characterized in that the recess (6) is constructed as a blind hole.12. Brake body according to one of claims 1 to 11, characterized in thatthe brake body comprises a carrier plate (1).
 13. Brake body accordingto claim 12, characterized in that the friction material element (3) isat least indirectly disposed on the carrier plate (1).